Verification of Delayed Permanent Lithium Intercalation into Graphite Interlayers by Surface Treatment of Lithium Ion Battery Anode

Abstract: High performance of lithium-ion batteries (LIBs), in terms of high capacity and stability, is in increasing demand for various applications in a variety of energy-related fields, including next-generation electric vehicles. In this regard, attempts have been made to form a stable and robust solid electrolyte interphase (SEI) on LIB anodes, which can stably maintain the cyclic process of Li ion insertion/extraction into/from the anode materials. In this study, we coat the surfaces of LIB anode materials consisting of graphite and silicon with poly(vinyl alcohol)-phosphate (PVA-PO4) to form a stable SEI layer with high ionic conductivity and adopt the Auger electron spectroscopy (AES) to clearly detect the LixC6 (x < 1) phase generated by the permanent intercalation of Li into graphite interlayers. A comparative analysis based on AES clearly demonstrates that permanent Li intercalation into graphite interlayers is delayed by the oxide coating, resulting in enhanced stability as well as reduced Li consumption at the anode.